Approaches that are, to our knowledge, novel, are proposed in this paper to improve the accurancy performance of self-mixing interferometruy (SMI). First the characteristics associated with signals observed in SMI systems are studied, based on which a new procedure is proposed for achieving accurate estimation of the laser phase.

Recent advances in smart textiles and wearable technologies based on piezoelectric fibers as wearable energy harvesters.

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to produce a new generation of smart garments.Such affordable smart garments could fulfil diverse applications, ranging from work wear in specific industries to the almost infinite scenarios of personal use including energy harvesting/storage, force/pressure measurement, porosity or color variation, and sensors (movement, temperature, chemicals). [1][2][3][4][5][6][7] However, performance, scalability, and cost problems have restricted the deployment of currently available smart textiles. To build smart textiles on an industrial scale, method of manufacturing and material selection are two important requirements. The approach of new energy materials and novel fabrication methods are essential to develop wearable technologies. Wearable energy generating devices that can be seamlessly integrated into garments are a critical component of the wearable electronics genre. Currently flexible fiber energy harvesters have attracted significant attention due to their ability to be integrated into fabrics, or stitched into existing textiles. Large-scale production of energy harvester fibers using conventional manufacturing processes, however, is still a challenge.Energy harvesting from environmental mechanical sources such as body movements including finger imparting, [8] pushing, [9] stretching, [10] bending, [11] twisting, [12] air flow, [13] transportation movement, [14] and sound waves [15] has attracted widespread attention to promote flexible self-powered devices. [16] The best common mechanical energy harvesting methods are based on piezoelectric materials. [17] Piezoelectric materials can be classified in three categories: piezoelectric ceramics, piezoelectric polymers, and piezoelectric composites. [18] Unlike the energy harvesters utilizing solar or thermal energy, performance of piezoelectric generators is generally not limited by environmental factors. [19] Piezoelectric generators have received massive interest in energy harvesting technology due to their unique ability to capture the ambient vibrations to generate electric signals. [20] The unique energy transduction of piezoelectric materials enables their applications in fields of energy harvesting, actuators, [21] sensors, [22] structural health monitoring, and use in biomedical devices. [23] Numerous approaches have been used to fabricate piezoelectric generators, such as coating, [24] spinning, [25] depositing, [26] and printing. [27] Wearable energy harvesting is of practical interest for many years and for diverse applications, including development of self-powered wireless sensors within garments for human health monitoring. Herein, a novel approach is reported to create wearable energy generators and sensors using nanostructured hybrid piezoelectric fibers and exploiting the enormous variety of textile architectures. It is found that high performance hybrid piezofiber is obtained using a barium titanate (BT) nanoparticle and poly(vinylidene fluoride) (PVDF) with a mass ratio of 1:10. These fibers are knitted to form a wearable energy generator that pr...

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Energy storage is a key requirement for the emerging wearable technologies. Recent progress in this direction includes the development of fiber based batteries and capacitors and even some examples of such fibers incorporated into prototype textiles. Herein we discuss the advantages of using the wet-spinning process to create nanostructured carbon based materials as wearable energy storage. The ability to control the physical, mechanical, electrical, and electrochemical properties of carbon nanotube based fibers holds great promise to develop smart polymeric structure as an energy storing materials including fibers and textiles. This is the first comprehensive review to discuss effect of nanostructured energy materials on the electrochemical properties of carbon nanotube based fibers which covers the various compositions, spinning and fabrication conditions on the performance of wearable energy storage.

In a recent published work we proposed a technique to recover the absolute phase maps of two fringe patterns with different spatial frequencies. It is demonstrated that a number of selected frequency pairs can be used for the proposed approach, but the published work did not provide a guideline for frequency selection. In addition, the performance of the proposed technique in terms of its anti-noise capability is not addressed. In this paper, the rules for selecting the two frequencies are presented based on theoretical analysis of the proposed technique. Also, when the two frequencies are given, the anti-noise capability of technique is formulated and evaluated. These theoretical conclusions are verified by experimental results.

Feedback parameter (the C factor) is an important parameter for a semiconductor laser operating in the regime of external optical feedback. Self-mixing interferometry (SMI) has been proposed for the measurement of the parameter, based on the time-domain analysis of the output power waveforms (called SMI signals) in presence of feedback. However, the existing approaches only work for a limited range of C, below about 3.5. This paper presents a new method to measure C based on analysis of the phase signal of SMI signals in the frequency domain. The proposed method covers a large range of C values, up to about 10. Simulations and experimental results are presented for verification of the proposed method. Abstract: Feedback parameter (the C factor) is an important parameter for a semiconductor laser operating in the regime of external optical feedback. Selfmixing interferometry (SMI) has been proposed for the measurement of the parameter, based on the time-domain analysis of the output power waveforms (called SMI signals) in presence of feedback. However, the existing approaches only work for a limited range of C, below about 3.5. This paper presents a new method to measure C based on analysis of the phase signal of SMI signals in the frequency domain. The proposed method covers a large range of C values, up to about 10. Simulations and experimental results are presented for verification of the proposed method. Disciplines Physical Sciences and Mathematics